Field of the Invention
The present invention relates to a sheet separation mechanism and a sheet-fed scanning apparatus using the sheet separation mechanism, and more particularly to a sheet separation mechanism with an annular member and a sheet-fed scanning apparatus using the sheet separation mechanism.
Description of the Related Art
A typical sheet separation mechanism may be applied to a scanner, a printer, a multi-function peripheral and the like to feed the sheets into a passageway separately. A conventional sheet separation mechanism includes a friction pad and a feeding roller working in conjunction with each other to perform the sheet separation operation according to the friction difference. The friction pad of the mechanism is usually in contact with a middle portion of the sheet. So, the middle portion of the sheet cannot be curled, but the sheet tends to be skewed. Another conventional sheet separation mechanism includes a reverse roller and a feeding roller working in conjunction with each other to perform the sheet separation operation. In this mechanism, two coaxial reverse rollers are usually adopted, and the sheet cannot be easily skewed, but the middle portion of the sheet tends to become curled owing to a gap between the two reverse rollers, and the sheet tends to become jammed or damaged.
United States Patent Publication No. 2014/0203495 discloses a sheet supply device, in which a sheet-pressing rocker arm with a special exterior design is disposed between the reverse rollers, and mainly functions to fill the gap between the two reverse rollers and to suppress the sheet from being curled upwards, wherein the shape of the front end of the rocker arm and the complicated mechanism are designed to form a movable closing portion to press the head portion of the sheet downwards so that the sheet cannot be twisted reversely by the reverse rollers to cause the paper jam. However, such the mechanism has the very complicated design and needs to be manufactured by the very complicated processes, and this is disadvantageous to the production cost, the assembling cost and the maintenance. Also, the mechanism tends to fail after being used for a long time, and the mechanism provides the sliding friction to the sheet and tends to wear the sheet.